Bag



May 21 l940 M. VOGEL-JORGENSEN 2,201,675

BAG

Filed Oct. 8, 1937 ATTORN EYS Patented May 21, 1940 UNITED STATES BAG Mikael Vogel-Jorgensen,

Frederiksberg, near Copenhagen, Denmark, assigner to F. L. Smidth & Co., New York, N. Y., a corporation of New Jersey Applicationv October 8, 1937, Serial No. 167,947 In Great Britain October 17, 1936 1 Claim.

This invention relates to block-bottom valve bags for containing pulverized or granular in aterials, and is concerned with bags which are closed by folding crossbottom parts one upon the 5 other and securing the overlapped parts together in any suitable manner.

En the manufacture of bags of the type referred to, it is desirable, for reasons of economy, to use as small an amount of paper as possible,

and, therefore, in folding the paper to forrn the bottoni of the bag, the shortest possible length of the tubular part of the bag is employed. The strength of the bottom of the bag depends on the manner of securing together the folded side flaps,

and if the overlap of the aps is too narrow, the bottom closure will be weak and, in addition, the valve projecting into the bag Will be so short as to be liable to be forced outward by the contents and thus permit leakage.

In order to increase the strength of the bottom of such a bag, and at the same time to increase the length of the valve, the use of a strip of paper affixed to the bottom so as to extend around the edge of the side flaps and into the valve has been suggested, but it has been found in practice that such av reinforcing strip frequently becomes cracked. This may be caused by the weight of the bag as the latter is supported on the lling spout or by the inside pressure 'exerted during the filling, and the result is tha-t the valve is liable to be forced outward in subsequent handling.

In an attempt to strengthen the bottom and lengthen the valve of such a bag, the walls of the bag have been cut through so as to provide separate side and end iiaps, and by this expedient, the side flaps may be made somewhat larger than would otherwise be the case. Such a procedure produces a longer valve and a larger Overlap between the side flaps so as to permit them to be secured together more strongly, but it introduces weakness at other places. Thus, in a bag of such construction, the paper near the corners of the bottom is liable to burst,

rendering the bag defective as well as injuring the valve.

The present invention is directed to the provision of a novel bag of the block-bottom type which overcomes the disadvantages of the prior bags above mentioned, and the new bag has additional advantages, which will be explained hereafter' in detail.

According to the invention, the side flaps of the cross bottom of the bag are enlarged and separated from the corresponding end flaps by cuts (Cl. 22S-62.5)

or cuts are separated when the side flaps are lli folded one over the other, and the reinforcing means extend lengthwise of the bottom beyond the incisions. A strong bag structure is thus produced which is free of the weaknesses of the prior constructions. 1i"

For a better understanding of the invention, reference may be had to the accompanying drawing,l in which Figure 1 is a plan view of the bottom of a bag of the invention showing the parts at one stage 20 in the folding;

Figure 2 is a view similar to Figure 1 showing the folding completed;

Figure 3 is a view similar to Figure 2 showing thev bag after the application of the reinforcing 25 means;

Figure 4 is a sectional View on the line 4-4 of Figure 3;

Figures 5 and 6 are sectional views similar to Figure 4 but of modified constructions; 30

Figure '7 is a view similar to Figure 3 of a inodication; and

Figure 8 is a sectional View on the line 8--8 of Figure '7.

Referring to the drawing, the bag illustrated 35 in Figure 1 `has the usual tubular section I0, at the ends of which have been made cuts extending in a direction parallel to the axis of the bag tube prior to the commencement of the folding operations, each cut separating one of 40 the side aps IIa, IIb from one of the end iaps I2a, i212. After inward folding of the end naps in the usual manner along the lines I3, the cut edges I4 of the end naps lie parallel to the greatest width of the bottom of the bag while the cut edges I5 of the side flaps lie at right angles thereto, as shown. The folding operations are completed by the inward folding of the side flaps Ila, I Ib along the lines A, B lying on opposite sides of the long axis of the bottom, and at this stage, the bottom of the bag is in the condition illustrated in Figure 2. The overlap of the side iiaps is such that the free edge ISa or IBb of each side iiap lies beyond the cut edges I4 of the end 55 flaps at the opposite side of the long axis of the bottom.

The length of the valve is then represented by the distance between the aligned edges I5 of the side aps and the end edge Il of an end flap, and at the end of the bottom opposite the valve, the portions of the end flap and side aps lying in overlapping relation are secured together, as by an adhesive. With the bottom so formed, the places of greatest weakness are at the points I8, I9 which are at the ends of the cuts, and to strengthen these points, a reinforcement is provided in the form of a strip 2D. This strip is of paper aflixed to the outer surface of the side ap IIa and is of such dimensions and is so placed that its inner end lies inward beyond the edge I 'l of the end flap and its outer end lies outwardly beyond the edges I5 of the side flaps. Preferably, when the end and side flaps at the corner opposite the valve corner are secured together by adhesive, a similar reinforcement 2I is used at that corner.

In the construction illustrated in Figure 5, the reinforcement employed at the valve end includes a strip 22 similar in dimensions and location to the strip 20 and a second reinforcing strip 23. The strip 23 is secured to the under surface of the upper valve flap, generally designated 24, and extends from a point inward from the inner edge Il of the lower Valve flap out beyond the outer edge of the upper flap. 'Ihe projecting ends of the reinforcing strips 22, 23 are then secured together, as shown. l/Vhen the reinforcing strip 23 is employed, affixed to the under surface of the under valve flap, the strip 22 may be omitted, if desired.

In the modified construction illustrated in Figure 6, the reinforcement consists of a single strip 25 which is affixed to the upper surface of the upper valve flap, extends outwardly beyond the edge of the ap, and is then folded back upon itself along the line 26 and affixed to the under surface of the upper valve flap. This construction is thus closely similar to that shown in Figure 5 except that the reinforcement is a single strip.

In the construction shown in Figure 7, a single reinforcing strip 21 is employed and the strip extends substantially the entire length of the bottom of the bag, one end being folded inward along the line 28 to provide a portion 29 which may be aixed to the under surface of the upper valve flap. The end 30 of the strip 21 overlies and is axed to the end flap I2b at the end opposite to the valve, and this portion of the strip reinforces and forms a strong closure for the corner which is to be permanently closed.

In a bag provided with a reinforcing strip 20, the strip may be employed as a means for closing the valve, if desired. For this purpose, the strip is carried out beyond the edges I5 of the side flaps and affixed to the upper surface of the end ap I2a. A strip thus employed both for reinforcing and closing purposes cannot, of course, be applied until after the bag has been filled.

What I claim is:

A bag having a valve in the bottom thereof and adapted during filling to be suspended from a lling nozzle inserted in said valve, comprising side and end flaps formed by longitudinal parallel cuts in the wall of the bag at the bottom end, the end flaps being folded inwardly towards one another so that said cuts form cut ends for the side flaps and cut parallel lateral edges for the end flaps extending inwardly in the direction of the long axis of the bottom from the cut ends of the side aps, and lying parallel to and on opposite sides of said long axis, said side flaps and the outer lateral portions of each end flap being folded inwardly towards said long axis so that the side aps lie one upon the other with their eut end edges aligned and the outer lateral portions of the end flaps are folded upon themselves, said side fiaps being secured to one another but being unsecured to at least the middle portion of at least one end flap to form the valve at the bottom of the bag, the in-folded, outer lateral portions of each end ap being spaced fromsaid long axis so that the respective outer ends of said in-folded portions diverge outwardly from points on said cut ends of the side flaps at opposite sides of said long axis, and a reinforcing strip secured to the outer surfaces of the side flaps, said reinforcing strip being of such width that the lateral edges thereof intersect the outwardly-diverging outer end of the infolded side portions of the respective end iiaps :if

at points on opposite sides of said long axis more than half the distance from the respective points on the cut end edges of the folded side flaps from which the outer ends of the infolded side portions of the end flaps diverge to the fold lines of said side aps, and extending, in the direction of said long axis, beyond the aligned cut end edges of the side flaps to provide an unsupported valve extension of generally trapezoidal shape, said reinforcing strip being turned back upon itself along the line determined by said opposite points and forming a fold-line defining the outer edge of said trapezoidally shaped portion, said turned-back portion extending back under said side flaps.

MIKAEL VOGEL-JORGENSEN, 

